JPH03505701A - metal honeycomb body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention is based on a metal honeycomb body, especially a catalyst carrier with a flow-mixing microstructure. In particular, it relates to a metal honeycomb body for use as a catalyst carrier in automobiles. Conventional Various shapes of metal honeycomb bodies are known from the technology of Regarding the shaping of the individual plates forming the cam body, consideration should be given to mechanical stability and individual The shape of the flow path is important. Furthermore, processing technology issues and the viewpoint of increasing the effective surface area are join in. This type of honeycomb body is disclosed in, for example, European Patent Application Publication No. 0159468. , No. 0220468, No. 0245737, and No. 0254738 It is described in.

For example, by connecting holes between individual channels or by corrugating each other diagonally and overlapping one another. The use of two plate layers to influence the macroscopic mixing of the flow in the honeycomb body. Various macro structures have already been proposed.

Further, in the specification of European Patent No. 0136515, a spiral shape is formed from alternating layers of flat plates and corrugated plates. In a honeycomb body wrapped in It has already been proposed to have one. Originally, processing and brazing of this type of honeycomb body This invention takes as a starting point the conventional technology that was developed in order to There is. In other words, by studying the effect of microstructure on flow, It was found that an auxiliary effect appears that promotes microscopic mixing of the flow.

This type of effect is caused by the geometrical relationship between the flat and corrugated sheets of a spirally wound honeycomb. It is also mentioned in European Patent Application Publication No. 0298943, which describes the Ru.

However, this effect has not been systematically exploited.

Therefore, the problem of this invention is to control the microscopic mixing in the individual channels of the honeycomb body. The effect of the catalytic structure can be exploited in a particularly advantageous way, thereby increasing the effectiveness of the catalytic action. An object of the present invention is to provide a metal honeycomb body that can be At the same time, the mechanical structure of the honeycomb body It seeks to favorably influence the characteristics.

In order to solve this problem, according to the present invention, the honeycomb shape, the average channel width and the main at least partially at least one first macrostructure that determines mechanical properties. A metal honeycomb body consisting of plates is used, with the honeycomb body being oriented in the flow direction. At least a portion of the plate has a plurality of channels with an average channel width that allows fluid to flow through the plate. has an auxiliary microstructure in at least a partial region, and this microstructure has an average channel width. 0601 to about 0.3 times the height of at least 15 μm, in which case the microstructure extends perpendicularly or at an angle to the flow direction, and extends from 1 to 10 mm in the flow direction. They are lined up consecutively at intervals. This shape is based on the following knowledge ing. In other words, the honeycomb body for the catalyst may have a unit cross section or a large number of (usually flat) (200 to 500 channels per square inch) for the total volume of the honeycomb body. and has a large internal surface. Catalyst as large as possible especially for effective catalysis Surface area is required. The effective surface area can be increased by coating with a layer of alumina. It can always be increased by more than 3 digits. The reason is that the crystalline material has many coarse cracks in the μm region. It is in the surface structure. However, for effective catalytic conversion, close to the wall Active exchange between the flow field and the central flow is also important (see Figure 7). honeycomb body The flow distribution curve illustrated for turbulent but especially laminar flow in the flow path of It has a velocity that decreases significantly towards the wall in the running area. The gas flow rate as a whole If the height is increased, the exchange near the wall will certainly be better, but if the height is increased in the honeycomb body, without sacrificing low throttling losses and short residence time of the gas in the catalytically active region. No. The rough surface of alumina itself is particularly rough due to its uniform roughness in the 10um region. Does not result in directional mixing. However, according to this invention, the surface roughness of alumina It is clearly thicker than the width of the channel (a dense continuation of individual plates that are clearly smaller than the channel width). The auxiliary microstructure significantly improves the microscopic flow conditions in all channels, especially near the walls. enable. Even though it causes little increase in flow losses, Numerous microscopic ridges on the wall lead to localized increases in gas flow velocity, and depressions increase gas flow velocity. resulting in local deceleration.

Advantageous embodiments of the invention are specified in the dependent claims. flat plate and corrugated plate In the case of a honeycomb body consisting of alternating layers, the corrugated plates form most of the channel walls. It is particularly advantageous to provide the corrugated sheet with a microstructure. with this kind of microstructure It is possible to process the corrugation of the board without any problems, and the corrugation and microstructure can be uniformly processed depending on the case. It turns out that it can be made in just one process. At least all channel walls It is generally advantageous to provide continuous microstructures in subareas.

The exact shape of the microstructure is not particularly important in this respect. The microstructure is , extending perpendicularly or at an angle to the direction of flow and extending toward one or both sides of the plate surface. It can consist of depressions, striations, knots, grooves, etc. that protrude from the surface. Of course all channels In order to have a uniform influence on the structure, it is effective to have a structure facing both sides of the plate. Of course Mi The black structure need not extend uninterrupted across the individual plates, but may be interrupted or connected to each other. It can extend out of alignment.

For the peripheral flow component in the direction toward the central flow, the microstructure is Exactly perpendicular placement is not necessarily important. Therefore, the microstructure is e.g. An angle α of between 75″ and 1.05° can be made with respect to the flow direction.

Not only does it generate a peripheral flow component in the direction of the central flow (but all When trying to create swirl in individual channels, the microstructure is (15° to 75″), preferably about 45″. this In the case of a seed shape, not only the peripheral flow component in the direction of the central flow but also the peripheral flow as a whole swirling occurs, both of which result in improved mixing.

In order to generate a particularly effective swirl in all channels, two plate layers are placed one above the other. to provide microstructures with angles of equal but opposite sign to the flow direction. This is effective. In this case, both microstructures of the plates forming one channel are approximately Since they complement each other in a helical microstructure, swirling is particularly promoted.

A machine direction dimension of 0.05 to 8 mm, especially about 0.5 to 3 mm, is suitable for the microstructure. It turned out to be advantageous. The height of the honeycomb structure is dependent on the height of the microstructure. Size matters. For the height of the microstructure, the average width of the channels is preferably approximately A factor of 0.05 to 0.1 has proven advantageous. Micro in flow direction The mutual spacing of the structures is between 1 and 10 mm, preferably between 2 and 8 mm, especially between 4 and 6 mm. be able to.

As expected, the microstructure does not necessarily interfere with the lamination or wrapping of plates. This is advantageous because it does not act as a bulge, but rather provides an auxiliary mechanical effect.

By harmonizing the shape, spacing and arrangement of the microstructures on the plate, it is possible to wrap, stack or twist them. It is possible to enable a geometrical interengagement of these structures in the contact area of the plates during assembly. , which not only makes it possible to subsequently braze the contact area without any problems, but also , supplementary mechanical strength of the entire honeycomb body can also be achieved. partially The microstructure can also compensate for linear expansion of the plate.

Formation of the microstructure is possible in various ways. For example, the formation of a cigarette is made of formed steel. between the roller and the rubber roller, or between two correspondingly shaped and optionally interlocking steel rollers. It can be done between Embossing of structures by intermittent processing is also possible . The microstructure is generally the better the plastic deformability of the plate is sufficient for its processing. becomes smaller.

An embodiment of the invention is schematically illustrated in the drawings, in which FIG. 1 shows a microstructure. FIG. 2 shows a cross-section of such a strip with an embodiment of the microstructure. Figure 3 is a cross-section according to Figure 1 to show another microstructure, and Figure 4 is in the flow direction. Figure 5 shows a strip plate with a microstructure that forms an angle to the FIG. 6 shows a strip plate having a micro structure based on the present invention and almost completely wrapped. FIG. 7 shows the flow conditions in the individual channels of the completed honeycomb body.

FIG. 1 shows a part of a strip 2 or 3, which strip extends in its longitudinal direction, i.e. It has a microstructure 5 extending at right angles to the flow direction.

FIG. 2 shows a cross section taken along cutting line II/III-II/III shown in FIG. 1, Furthermore, one of a plurality of modified examples of the microstructure 5 based on the present invention is shown. strip 2 or 3 has a plurality of grooves 6.7 extending approximately in parallel, and the distance a between these grooves is 1 to 10 mm, for example about 2 mm. Individual peaks of microstructure 6 Alternatively, the dimension of the valley 7 in the flow direction can be, for example, about 0.1 to 0.5 mm. Wear.

The maximum height of the microstructure with respect to the surface of the strips 2 or 3 is determined by the flatness of the channels in the honeycomb body. It should be a fraction of the uniform width, for example about 0.05 times. Microstructure as an absolute value is an example For example, the height can be 15 to 100 μm.

FIG. 3 shows another embodiment of the microstructure, in which individual ridges 8 and depressions The area 9 has a substantially embossed groove or depression shape.

FIG. 4 shows that the microstructures 5 on the strips 2 or 3 form an angle α with respect to the subsequent flow direction S. Show what you can do. For highly effective lateral mixing, the microstructure It is not necessary to make it perpendicular to the direction of rotation, but it can be deviated from the perpendicular direction by about 15 FIG. 5 shows that for special purposes, the microstructure on the strip 2 or 3 with respect to the subsequent flow direction S is It is shown schematically that even smaller angles between structures 5 can also be considered.

The angle α is, for example, approximately 45° in order to generate a swirl in all individual channels. The angular range can then be ±( depending on the dimensions of the flow channel and the flow velocity in the flow channel). 15° to 75e).

FIG. 6 shows the honeycomb body l in a state just before completion. Honeycomb body 1 is in the through-flow direction A macroscopically flat strip 2 with a microstructure 5 extending at right angles to the direction S and a through-flow direction from a macroscopically corrugated strip 3 having an auxiliary microstructure 5 perpendicular to the direction S; Become. The average width of the individual channels 4 is shown. If the first macro structure is As long as the waveform is created by the volute tooth profile, the average channel width is generally the first It has approximately the same size as the average wave height of the microstructure. Therefore, the size of the second macro structure Wave height can also be related to wave height. In particular, the wave height and average channel width are the same throughout the honeycomb body. There are macro structures that cannot be precisely defined. This invention can be applied similarly. For this type of case, where the average channel width is should be understood as the average interval of In the case of a simple structure, this is compatible with the dominant wave height. respond. Helically wound catalyst carriers provide multiple possibilities for applying this invention. This is just one example. The microstructure as known in the prior art is Suitable for improving honeycomb bodies consisting of laminated or twisted strips.

FIG. 7 shows the flow velocity distribution in the individual channels 4 of the honeycomb body. In the peripheral area of the channel The flow is relatively slow, and in the case of laminar flow, there is almost no exchange with respect to the central flow in the center of the channel. It's never done. Channel 4 is partially defined without a microstructure for comparison. Plate 3 does not affect this flow velocity distribution. However, the plate with the microstructure 5 2 is precisely the catalytically effective peripheral edge without excessively increasing the pressure drop in the channel 4. Brings flow mixing into the area.

The invention achieves catalytic action in the exhaust gas catalyst by microscopic swirling of the flow in the individual channels. for example in automobile exhaust gas catalysts without any other significant disadvantages. can have conversion rates that are several percent higher.

II/III IG 3 international search report international search report

Claims (1)

[Claims] 1. the honeycomb body (1) at least partially comprises at least a first macrostructure; This macrostructure has a honeycomb shape, average channel width (b) and and determine the main mechanical properties of the honeycomb body (1) in one flow direction (S). It has a plurality of channels (4) with an average channel width (b) through which a fluid can flow, 3) has an auxiliary microstructure (5) in at least a partial region. and the microstructure is at least 0.01 to about 0.3 times the average channel width (b). 15 μm height (h), with the microstructure (5) facing the flow direction (S). flowing at right angles or at an angle (α) and spaced at intervals of 1 to 10 mm. A metal honeycomb body characterized in that it is continuously provided in a direction (S). 2. The honeycomb body (1) consists of alternating layers of flat plates (2) and corrugated plates (3) or consisting of a layer of corrugated sheet, with at least a part of the corrugated sheet (3) having a second microstructure. The honeycomb body according to claim 1, characterized in that it has (5). 3. The second microstructure (5) consists of depressions, striations, knots, grooves, etc. (6, 7, 8, 9). and these microstructures are perpendicular or at an angle (α) to the flow direction (S). characterized by extending and protruding from the surface of the plate (2, 3) towards one or both sides The honeycomb body according to claim 1 or 2. 4. The microstructure (5) is 75° to 105° to the flow direction (S), preferably about 9 Honeycomb according to claim 1 or 2, characterized in that it extends at an angle (α) of 0°. Mu body. 5. The microstructure (5) is preferably ±(15° to 75°) with respect to the flow direction (S). extending at an angle (α) of approximately 45°. Honeycomb body. 6. The angle (α) between the microstructure (5) and the flow direction (S) overlaps one above the other have approximately the same size but opposite signs for the two plate layers. The honeycomb body according to claim 5. 7. the second microstructures (5) are between 2 and 8 mm from each other, preferably between about 4 and 6 mm; The honeycomb body according to claim 1 or 2, characterized in that it has a gap (a). 8. The second microstructure (5) is 0.05 to 8 mm in the flow direction (S), preferably Claim 1 or claim 1 characterized in that it has an extent or length (e) of about 0.5 to 3 mm. is the honeycomb body described in 2. 9. The second microstructure (5) has a height of approximately 0.05 to 0.1 times the average channel width (b). The honeycomb body according to claim 1 or 2, characterized in that the honeycomb body has a length (h). 10. All plates (2, 3) of the honeycomb body (1) have a second microstructure (5) In this case, the shape, spacing and arrangement of the microstructures are determined in the contact area of the plates (2, 3). 3. The microstructure according to claim 1 or 2, characterized in that it assists the geometrical interengagement of the microstructures. Honeycomb body. 11. The honeycomb body (1) is, for example, a catalyst carrier for an automobile exhaust gas treatment device. The honeycomb body according to claim 1, characterized in that: